What causes cyclonic storms


To form a cyclone, warm, moist air over the ocean rises upward from near the surface. … So basically as the warm air rises, it causes an area of lower air pressure below. Air from surrounding areas with higher air pressure pushes in to the low pressure area.

Cyclone is the specialized term for the procedure of tempest development that leads eventually to what are called sea tempests, hurricanes, or tropical violent winds in different parts of the world.

– High ocean temperatures of no less than 26.5°C
– Focalizing winds close to the sea surface constraining air to rise and frame storm mists.
– Adequate separation from the equator for a turn, for example, the Carioles’ drive to produce results.

The primary wellspring of vitality for tropical tornado’s is the warm seas in the tropical locales. To start a tropical twister the ocean surface temperature by and large should be over 26.5°C. In any case, existing typhoons frequently persevere as they move over cooler waters.

The advancement of a tropical violent wind likewise depends on good expansive scale wind administrations and can persevere for a few days with many after very whimsical ways. They lose their wellspring of vitality when they move over land or colder seas making them scatter.

  • Cyclones are formed only over large water bodies like oceans as they require warm water to begin with (at least above 27 degrees Celsius) — which also suggests that they are always formed near the equator.
  • Say, a certain region of air over the ocean has warmed up. Warm air, being lighter in weight, rises upwards. This displacement of a huge mass of air upwards creates an area of low pressure beneath it.
  • Air moves from the surrounding high pressure area to this newly formed low pressure area. The rotation of the Earth bends these currents of air towards the centre (called the Coriolis Effect. See Figure 2) creating forces acting around the centre as in this image:


  • The diagram I have shared here is of a Couple, a pair of forces, which when acting around a centre creates a rotational force around it. Similarly, high pressure gusts of air moving towards the low pressure area creates a rotational force around the eye.
  • Now, if the air is not warm enough to begin with and the rate of updraft is no match for this inward movement of high pressure air, a cyclone would never form.
  • However, if the air is sufficiently warm, coupled with wind and temperature conditions that facilitates constant updraft of warm air, it would result in a constant flow of high pressure air towards, and as a result, around the centre.
  • Meanwhile, the warm air (laden with water vapour) that has risen up cools down, forming huge Cumulonimbus clouds which could grow to be a few kilometres high.
  • Couple these huge clouds with rotational wind swirling around the eye — and when wind speeds reach over 64 Km/hr, we have what we call a tropical storm. And, when the speed clocks 120 km/hr — tropical cyclones !Cyclones rely heavily on warm air to fuel itself. Hence, once they make landfall, they precipitate heavy rains, but weaken in strength and fizzle out eventually.
  • Cyclones move from the point of their origin around the equator to other places due to wind directions — which depend heavily upon the rotation of the Earth from West to East. Also, very less cross-equatorial wind exists, which is why no cyclones move from one hemisphere to the other.
  • The rotation of the Earth also causes the cyclones to rotate around its eye in a specific direction — those formed in the Northern Hemisphere moves counter-clockwise, and the direction is clockwise in the Southern Hemisphere. This motion can be attributed to what is called the Coriolis Effect.
  • As you can see in the image below, the wind exactly over the equator experience a zero net Coriolis force, which is why cyclones never form directly over the equator. They are always formed at least 4 degrees away from the equator, to the North and South.


Coriolis Effect can be demonstrated using flushes too. Here’s an experiment : Fill a tub of water with a plug underneath. Take all possible precautions to dampen out any vibrations to the system and ensure it is as still as possible. Once this has been ensured, pull the plug. The water leaving the tub through the hole will create a swirl. If done in the northern hemisphere, this swirl will be counter clockwise, and clockwise in the southern. But remember, any little vibration can set off a motion in the other direction, too, which is why this is quite difficult to carry out.

Other real-world occurrences of Coriolis Effect can be seen in the bending of a football when in flight, or a cricket ball when given an adequate spin. In the video below, observe how the ball curves mid-air before it pitches.

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